Siren



. Feb; 22, 1927. I

R. R. M CLURE SIREN Filed Sept. 1'7. 1925 Even Z01".

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Patented Feb. 22, 1927. f v

UNITED. srA'r-es PATENT: orFic-afw RALPH n. McCi-URE, or SAN FRANCISCO, oALIroRNiA. ASSIGNOR T0 JOHN H.

Rossrrrna; or san raimcrsco, CALIFORNIA;

SIREN.

Application filed September 17, 1925. Serial No. 56,919.

' This invention relates to sound producing devices and more particularly sirens, and

has for its principal object to provide a hood or horn of the type designed'for directing the sound wave emitted by a siren 111 a given direction preferably a line parallel with the 'axis of rotation'of the rotor; The

invention consists preferably in means in the form of a tubular sound directing member inwardly into which the air to the rotor passes and outwardly through .which the sound emitting from the action of the rotor flows, and that embodiment illustrated consisting of a ported plate overlying a rotor provided with radially open ended channels and including a hood. extending forwardly from the plate and inwardly throughwhich the air passes into the channels and outward ly through which the soundpasses from the plate ports.

In sirens in general use as at present de signed, the air is admitted to. the rotor through the center of its axis andthesound is emitted in 'a' radial path, and is not directed in any particular path, thus the efficiency of the sirenfor directional signalling is materially reduced. I

This invention is particularly useful in directingcertain sound waves in a particular path where directional signalling is desired thereby increasing the'efliciency of the siren for this-purpose'and reducing the objections without departing from the spirit or sacrificing any of the advantages of the invention.

To more fully comprehend the invention, reference is directed to the accompanying drawings, wherein.-

Fig.1 is a view in side elevation of the preferred embodiment of my invention.

. Fig. 2 is a vertical longitudinal section.

Fig. 3 is a view in front elevation of a siren rotor. 1

Fig. 4: isa viewin longitudinal vertical section of an embodiment of the invention wherein the base plate forms a mounting for a parabolic sound deflector and wherein the bell mouthed core member falls short of eX- V tending. flush withth'e' edge of the deflector.-

Fig. v5 is a view looking into the construction illustrated in Fig-l4, and

Fig. 6 is a vertical sectional view taken I on line. 6,, 6 of Fig. 3. j 1 Referring to the drawings wherein like characters of reference designate corresponding parts throughout the several views,

.L indicatesa standard carrying a motor casing 2 detachably secured thereto by a bracket 3. The casing is'provided with an annular flange lto which is secured therea-r face of Y abase plate 5. The plate is provided in its rear with .a'recess 6*and the wall of" said plate is inclined outwardly toward the center of the plate as at 7," andis'further provided in said inclined portion with an annu lar series of sound outlet ports 8. Within said series of ports 8 the plate is provided with an opening orportfi, and as illustrated in Fig. 2 there extends-outwardly, from said port a tubular bell mouthedfinwardlytaperto the base plate 5 at a point beyond the limits of the annular series of openings 8.

The parabolic deflector directs the, sound directing member 11 secured atits inner end waves passing through the ports 8 outwardly in. a path surrounding the'core 10.-

Within the recess 6 is rotatably mounted a siren rotor .12 carried on the end of a motor shaft or other rotating means 13, and the rotor is provided with a plurality'of radial channels 14 openinga't their outer ends in registry with the portsr8 and communicating at their inner ends with the air inlet 9.. The rotation of the rotor '12 causes airto pass inwardly through'the core'in the direction of the arrow through the channels 14 in the direction of the arrow, outwardly through ports 8 and outwardly through the space between the parabolic generator 11 and the outer surfaceof the core IOasindicated by the arrow, thus it will be observed that the sound waves are directed by the hood in a direction substantially parallel with the axis of rotation of the rotor, and are precluded from emission radially of the rotor casing as is the common practice,

In Fig. 4, the tapering core 10 has been materially reduced inlength as it terminates at a point well within the deflector 11. In this construction as well as in the preferred embodiment, the parabolic sound deflector is employed, and while this form is preferable, showing the greatest efficiency in sound direction, it is to be understood that its shape may be departed from if desired;

Hav ng thus described my inventlon what I claim as new and desire to protect by Let- I ters Patent of the United States is L'In combination withithe rotor of a siren provided with open ended channels,

said channels disposed radially of the rotor with their outer ends opening toward one face of the rotor near its periphery and the inner ends opening toward the same face of the rotor near its center, a ported plate overlying the face of the rotor and provided centrally with a port common to the inner ends of said rotor channels and with an annular series ofports with which the outer ends of said channels register onthe movement of the rotor, and a hood extending forwardly from said plate near its periphery and inwardly through which air passes into said central port and outwardly through which the soundip'asses from said annular series of ports. r Y 2; A sound directing and a1r inlet hood for sirenscomprising a plate provided cen' trally with a port and further provided with an annular'serie's of ports surrounding said central port, and a pair of concentrically arw member earned by and extending outwardly from the face of the plate and said member being of a diameter to enclose said series of sound outlet openlngs. 4. A sound directlng and air inlet hood for sirens comprising an open ended tubu lar member, its inner open end being circumferentially flanged outwardly and said flange being provided with aplurality of sound outlet openingsv disposed circumferentially of the tubular member, and a second directing member extending outwardly from the periphery of the flange with said first tubular member disposed centrally thereof, the inner member falling short of projecting beyond the end of the outer tubular member. 1 i

5. A sound directing and air inlet hood for sirens including a base provided with an air inlet opening and a plurality of sound,

outlet openings and a tubular sound directinghood extending from one face of the plate, said sound directing hood mouth and said air inlet opening being disposed in rela tive concentric relation with the end of said air inlet opening. falling short of projecting beyond the end of said hood mouth,

In testimony whereof I have signed name to this specification.

RALPH n. MCCLURE. 

